Ask your own question, for FREE!
Mathematics 10 Online
MsBrains (ms-brains):

Can someone walk me through this problem! I have been stuck on it! I WILL MEDAL!!

MsBrains (ms-brains):

jimthompson5910 (jim_thompson5910):

were you able to graph this system?

MsBrains (ms-brains):

Not yet, Give me a sec!

jimthompson5910 (jim_thompson5910):

alright

OpenStudy (anonymous):

alternatively you can check which ordered pair works

MsBrains (ms-brains):

Do I graph x > - 2 or the one under it?

jimthompson5910 (jim_thompson5910):

you graph them both on the same xy coordinate grid

jimthompson5910 (jim_thompson5910):

what does x > -2 look like?

MsBrains (ms-brains):

The graph looks like this

jimthompson5910 (jim_thompson5910):

very good, now how about the other inequality

MsBrains (ms-brains):

Like this

jimthompson5910 (jim_thompson5910):

ok imagine them both plotted together what does the overlapping region look like?

MsBrains (ms-brains):

It would be (-2, -3.5)

jimthompson5910 (jim_thompson5910):

are you able to see what the overlapping region looks like?

jimthompson5910 (jim_thompson5910):

it might help to start with the second inequality you posted, then shade out x > -2 on top of it

MsBrains (ms-brains):

I am supposed to be checking each choice for the correct answer by switching the x,y with the choices?

jimthompson5910 (jim_thompson5910):

yes that's another way to check

jimthompson5910 (jim_thompson5910):

for example, let's focus on just choice A for now that is (x,y) = (-3,-1) since x = -3 and y = -1 we can plug them into each inequality x > -2 -3 > -2 ... replaced x with -3 -3 > -2 is FALSE, so (-3,-1) is NOT a solution to the system

jimthompson5910 (jim_thompson5910):

you need to see which point makes both inequalities true

MsBrains (ms-brains):

Okay. so (-1, 6) -1>-2 is not false 6 ≤ 2(-1) +7 6 ≤ 5 There is no solution to that.. ^^Is that how I can check it? @jim_thompson5910

jimthompson5910 (jim_thompson5910):

your work looks good since 6 ≤ 5 is false, that means (-1,6) is also not a solution. So move onto the next answer choice

MsBrains (ms-brains):

Next; (-1, 4) -1>-2 is not false 4 ≤ 2(4) +7 Many Solutions

MsBrains (ms-brains):

What do we do when it has many Solutions @jim_thompson5910

jimthompson5910 (jim_thompson5910):

4 ≤ 2(4) +7 simplifies to 4 ≤ 15 which is true since both inequalities are true, this means (-1,4) is a solution now check choice D

jimthompson5910 (jim_thompson5910):

wait a second

jimthompson5910 (jim_thompson5910):

you plugged in the wrong x value

jimthompson5910 (jim_thompson5910):

4 ≤ 2(4) +7 should be 4 ≤ 2(-1) +7 notice how x is -1

MsBrains (ms-brains):

Yes, that would equal to 4 ≤ 5

jimthompson5910 (jim_thompson5910):

that's also true, so (-1,4) is still a solution

MsBrains (ms-brains):

(1,11) 1> -2 Many solutions 11 ≤ 2(11) +7 Many solutions

jimthompson5910 (jim_thompson5910):

in the second inequality, you replaced x with the wrong x value

MsBrains (ms-brains):

What should it be replaced with?

jimthompson5910 (jim_thompson5910):

with 1 since the first number of (1,11) is 1

MsBrains (ms-brains):

11 ≤ 2(1) +7 no solution

jimthompson5910 (jim_thompson5910):

yes since the right side turns into 9 which is NOT greater than 11

jimthompson5910 (jim_thompson5910):

or equal to it

jimthompson5910 (jim_thompson5910):

so D is not a solution

MsBrains (ms-brains):

C (-1, 4) was the only solution, which means it's correct?

jimthompson5910 (jim_thompson5910):

here's a visual way to look at it See the attached image for the graph of the inequalities and the points plotted. The only point in the red solution region is point C. The other points are outside of the solution region. So only (-1,4) is the solution.

jimthompson5910 (jim_thompson5910):

yes only C is the solution

MsBrains (ms-brains):

Wow. That actually made so much sense. :P Thank you so much for the help!

jimthompson5910 (jim_thompson5910):

no problem

MsBrains (ms-brains):

Do mind check the 4 other after I am done solving them?

MsBrains (ms-brains):

checking*

jimthompson5910 (jim_thompson5910):

sure I can help out with that

MsBrains (ms-brains):

Is this an easier way to figure it out, or do I have to check each problem like before?

jimthompson5910 (jim_thompson5910):

looks great. That's the only point in both shaded regions...aka the final shaded solution region

jimthompson5910 (jim_thompson5910):

the other points are in the red shaded region, but NOT in the blue shaded region. They would need to be in both

MsBrains (ms-brains):

Okay! Awesome! You wouldn't belive how much trouble I have been having with this. Thank you so much!

jimthompson5910 (jim_thompson5910):

I'm glad it's making more sense now

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!